Question: Express your answer in scientific notation. $1.4\cdot 10^{9} - 8.6 \cdot 10^{8} = $
Solution: $\phantom{=}{ 1.4\cdot 10^{9}} - 8.6 \cdot 10^{8}$ $={14\cdot 10^{8}} - 8.6 \cdot 10^{8} $ $= (14-8.6)\cdot10^{8}$ $= 5.4\cdot10^{8}$